This invention is directed to a print character selection mechanism for printers of the type wherein print characters are selectively rotated into a print position and are selected by deenergizing an electromagnetic coil associated therewith, and in particular, to a print character selecting mechanism that substantially reduces the time required to effect positioning of a print character at a print position by reducing the time required to displace a selection member into engagement with the character rings after the electromagnetic coil is deenergized.
Heretofore, print character selection mechanisms for printers having a plurality of character rings, each character ring having print characters circumferentially disposed thereabout, have taken on various forms. In particular, print character selection mechanisms, wherein an electromagnetic actuating coil is formed about a displaceable yoke member, which yoke member in combination with a yoke member that is common to each of the other displaceable yoke mechanisms, define a closed magnetic flux field when the electromagnetic coil is energized and have been found to be less than completely satisfactory. Specifically, by utilizing a common yoke member for defining a closed magnetic flux path in each of the displaceable yoke members, if selection of a specific print character is effected by a deenergization of the electromagnetic coil, the magnetic flux fields induced in the adjacent character ring selection members are redirected by the common yoke in the same direction as the closed flux loop maintained by the electromagnetic coil, when the coil is energized, thereby delaying the selection of the print character until the redirected magnetic flux field, caused by the adjustment element, is overcome. The additional delay time, in addition to rendering the operation of the print character selecting mechanism less reliable, also requires that the time of the printing cycle be increased in order to take into account any additional unwanted magnetic flux fields caused by adjacent character ring selection members. Accordingly, a print character selection mechanism that eliminates the aforementioned disadvantage is desired.